Electronic soil watering system



March 12, 1957 YOUNG ETAL 2,785,006

ELECTRoNC SOL WATERNG SYSTEM Fi1ed Apri1 10 1956 ZN; E'VTORIS CHARLES H(YoLG DAMEL j. GALAS 0 ATT NEY vice vhen the Sil reaches a predeter1inedTesistance Vaue and Said Second 0entiOmeter providing for the SeIecG ofadditi0nav01tag6 fr0n the Second Secondary; a reay connected t0 Saidanode of the electronic diS ChaTge device and a pair of Switchesactuated by Said reay, One of said Switches COnr0lling the povver SupplyfO` Operating Said valve and the 0ther switch being in cCuit With theSc0nd pOtentOneter for Supplying Said addGnal V0Itage t0 the Controlgrid rneans and said Ca ...acOr beng operative to Shift the phase 0f theSglal vohage /hen the s0il to be Watered is of type having a lovvresistance value.

4. Zn elect1-ica1 C0I1tr0l as in clain1 3 further characterized by Saidcontr01 grd Ineans c0mprising a pair of grids arranged in aralel toincrease the Sensitivity 0f the gaseous dischafge device Whereby Saiddevice Will be eifective under the Signal v01tage to nlaintain the valveopeI1 0nly a sh0l t )eri(d to supply only a Small anunt of v/ater t0 theSoil Zn electrical control fof cuding a s0en0id 0perated valve, Whichcon1prises a Sensing robe disposed in the soil t0 be watered, a hyrar()nhaving a cathode, an anode and control grid n1canS, a tanSOn1er having aPrinlary connected to a SO1c 0f aternating l)()tentia1 and a TSt andSecond Secondafy affanged 180 out of phase and being of relavey IOV andTelatively high 1)0tential respectively; a rSt circit including Saidiirst SecondaTy in series vvith a rSt p0tentiometer, Said Sensing probe,Structure 0f the a soil Watering systen in Watering systeln and Saidcontfol grid nleanS; a Second Circui inciuding said Second Secondary inseries With Said cathode, Said anode and a Second p0tenti0meter; Saidfirst potentionlete1 pfo-'iding for the Selection of a signal v0tagefronl ihe rSt Secondary vhich iS eective to bias he contr0l grid Ineansand Te the Thyrar0n When the SO reaches a pTedetennned fe8istance valueand Said Second potenti0neter providing for the Selection of addiionalV0}tage from the Second secondary; a Telay con nected t0 Said anode anda pair of Svvitches actuated by 5aid relay, one of Sad Switchescontrolling the pover Supply fof operating Said valve and the otherswitch being in circuit vvith the Second )()tenti()I1eter for SupplyingSaid additional v01tage 180 out of phase With the Signal v0ltage, t0 thecontro1 grid X11eans in order to be eective to cancel out son1e 0f thesignal voltage whereby the Thyratron under the inuence of the additiona1Voltage yvill Inaintain the valve ope11 until the Soil resistance iS decreased to the value for Which the first p0tentiometer is Set.

Refeences cite(l il1 the me of this patent UNITED STATES PATENTS 2 57898l Parker Dec. 18 19jl 2 S99 862 Ray Iune 10 1952 2,61l,643 HigginsSept. 23 1952 z 69 976 IIasenkanp 1Iov. l94

